The present invention relates to a portable, handheld, power tool which is used to rotate a tap and thread an opening in a workpiece.
A known tap wrench has a pair of handles which extend in opposite directions from a chuck which holds the tap. When a hole or opening in a workpiece is to be threaded, the tap is aligned with the opening. Force is manually applied against the handles of the wrench to rotate the tap. When the hole or opening has been threaded, the direction of rotation of the tap is reversed to disengage the tap from the opening. A tap wrench having this general construction and mode of operation is disclosed in U.S. Pat. No. 4,799,832.
Power tap units have previously been used in relatively large machines having a construction similar to the construction of a drill press or a milling machine. In order to tap an opening in a workpiece, a machinist must set up the power tapping unit in the machine, bring the workpiece to the machine, and then operate the machine to tap an opening in the workpiece. The configuration and/or size of the workpiece may block access of the known power tapping machine to the opening in the workpiece or may prevent the workpiece from being positioned relative to the machine. This has previously resulted in the use of a manual tap rather than a power tap to form threads in the openings in certain workpieces.